Bell housing change - The 1947 - Present Chevrolet & GMC Truck Message Board Network

69ChevyLB · 11-27-2004, 01:41 AM

Need to pull my Saginaw 3 speed and have an M20 Muncie I want to replace it with. Is it 100% necessary to replace the bell housing to one with the smaller bearing retainer hole or make a spacer for the bearing retainer? Will the bearing retainers interchange? Once the tranny is bolted up it shouldn't move so why the need for the bearing retainer to fit tight in the bell housing? The reason I am asking these questions is I need to get the truck on the road as soon as possible. One other question. The 4 speed has the speedo connection on the passenger side so what do I do for a cable for it?

JimKshortstep4x4 · 11-27-2004, 04:59 AM

The bearing retainer is used to align and center the transmission to the crankshaft when the transmission is installed. Without the fit of the retainer inside the bell housing, there is a good chance that the input shaft will be misaligned. I believe the concentric spec is .005 max TIR, so if the transmission is not centered, problems could develop.

A properly made spacer should work, but it would have to be accurately made. I am not sure how you would hold the spacer in place. Also, without the retainer to center the transmission, I am not sure how else it could be centered.

If you decide to look for another bell housing, be sure to measure the hole as not all bell housings will fit the Muncies.

On your speedometer question, you can get longer cables and route the cable over the top of the transmission to connect to the speedo gear housing. The cable on my 65 SS is clamped to the floor to keep it out of the way.

Jim

MOTHERTRUCKERS · 11-27-2004, 08:15 AM

Let me know the size you need and i'll go through my pile. 20.00 + shipping if i have the right one. Muncie's are great when installed correctly, when not they break the ears off at the bellhousing and totally destroy the floor, your shin and your driveshaft.

69ChevyLB · 11-27-2004, 05:37 PM

Thanks. I measured the OD on the bearing retainer and it's 4.682" so if you have a bellhousing that measures 4 11/16 or a hair bigger I will take it. Figure shipping to 44721.

MOTHERTRUCKERS · 11-27-2004, 08:39 PM

I'll check tomorrow, you can call tollfree between 10am-4pm if you want to.

MOTHERTRUCKERS · 11-28-2004, 05:59 PM

Every one i have is 4 15/16 sorry.

69ChevyLB · 11-28-2004, 07:57 PM

Thanks for looking Ed. I'll keep looking elsewhere.

Ralph

Willy Prost · 11-28-2004, 08:10 PM

I had a spacer made by a machine shop to make up the difference from 4.684in. on a Tremec 3550 retainer bearing to the 5.124in. needed for the 68-72 chevy truck bellhousing.

The spacer is held in place by being an interference fit. The machinist explaned that the outside of the retainer was 4.684in. then the inside of the spacer would be 4.683in. The spacer was then heated and then pressed on the retainer while still hot. After the two joined pieces cooled, they were chucked back in the lathe to make sure that the outside dimention of the retainer was now 5.124in. to match the original retainer that was on the original 3-speed transmission.

11-27-2004, 01:41 AM	#1
69ChevyLB Active Member Join Date: Aug 2004 Location: Canton, OH Posts: 249	Bell housing change Need to pull my Saginaw 3 speed and have an M20 Muncie I want to replace it with. Is it 100% necessary to replace the bell housing to one with the smaller bearing retainer hole or make a spacer for the bearing retainer? Will the bearing retainers interchange? Once the tranny is bolted up it shouldn't move so why the need for the bearing retainer to fit tight in the bell housing? The reason I am asking these questions is I need to get the truck on the road as soon as possible. One other question. The 4 speed has the speedo connection on the passenger side so what do I do for a cable for it? __________________ 69 C10 LWB Project 47 Cushman Scooter Project It is better to have loved and lost than to live with a psycho all your life.

11-27-2004, 08:15 AM	#3
MOTHERTRUCKERS Registered User Join Date: Dec 1999 Location: BRADENTON FLA Posts: 3,269	Let me know the size you need and i'll go through my pile. 20.00 + shipping if i have the right one. Muncie's are great when installed correctly, when not they break the ears off at the bellhousing and totally destroy the floor, your shin and your driveshaft. __________________ Rest in Peace Ed. Thanks for all the good times.

11-27-2004, 05:37 PM	#4
69ChevyLB Active Member Join Date: Aug 2004 Location: Canton, OH Posts: 249	Thanks. I measured the OD on the bearing retainer and it's 4.682" so if you have a bellhousing that measures 4 11/16 or a hair bigger I will take it. Figure shipping to 44721. __________________ 69 C10 LWB Project 47 Cushman Scooter Project It is better to have loved and lost than to live with a psycho all your life.

11-27-2004, 08:39 PM	#5
MOTHERTRUCKERS Registered User Join Date: Dec 1999 Location: BRADENTON FLA Posts: 3,269	I'll check tomorrow, you can call tollfree between 10am-4pm if you want to. __________________ Rest in Peace Ed. Thanks for all the good times.

11-28-2004, 05:59 PM	#6
MOTHERTRUCKERS Registered User Join Date: Dec 1999 Location: BRADENTON FLA Posts: 3,269	Every one i have is 4 15/16 sorry. __________________ Rest in Peace Ed. Thanks for all the good times.

11-27-2004, 04:59 AM	#2
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	The bearing retainer is used to align and center the transmission to the crankshaft when the transmission is installed. Without the fit of the retainer inside the bell housing, there is a good chance that the input shaft will be misaligned. I believe the concentric spec is .005 max TIR, so if the transmission is not centered, problems could develop. A properly made spacer should work, but it would have to be accurately made. I am not sure how you would hold the spacer in place. Also, without the retainer to center the transmission, I am not sure how else it could be centered. If you decide to look for another bell housing, be sure to measure the hole as not all bell housings will fit the Muncies. On your speedometer question, you can get longer cables and route the cable over the top of the transmission to connect to the speedo gear housing. The cable on my 65 SS is clamped to the floor to keep it out of the way. Jim

11-28-2004, 07:57 PM	#7
69ChevyLB Active Member Join Date: Aug 2004 Location: Canton, OH Posts: 249	Thanks for looking Ed. I'll keep looking elsewhere. Ralph __________________ 69 C10 LWB Project 47 Cushman Scooter Project It is better to have loved and lost than to live with a psycho all your life.

11-28-2004, 08:10 PM	#8
Willy Prost Senior Member Join Date: Jan 2000 Location: Arlington, VA Posts: 398	I had a spacer made by a machine shop to make up the difference from 4.684in. on a Tremec 3550 retainer bearing to the 5.124in. needed for the 68-72 chevy truck bellhousing. The spacer is held in place by being an interference fit. The machinist explaned that the outside of the retainer was 4.684in. then the inside of the spacer would be 4.683in. The spacer was then heated and then pressed on the retainer while still hot. After the two joined pieces cooled, they were chucked back in the lathe to make sure that the outside dimention of the retainer was now 5.124in. to match the original retainer that was on the original 3-speed transmission.



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